Carbon...................................................94.5
Kaolin..................................................... 3.1
Silicic acid............................................... 1.6
Oxide of iron........................................... 0.4
Chalk and magnesia................................. 0.2
Foreign matter......................................... 0.2
100.0
The Faber Manufacture, ca. 1850. Courtesy of Faber-Castell AG.
Quotes by Henry Petroski, The Pencil. A History of Design and Circumstance. London & Boston 1989
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